Protein

Proteins are of great importance to anyone who is training with the intention of building muscle or increasing athletic performance. Lack of protein can cause growth failure, loss of muscle mass, decreased immunity, weakening of the heart and respiratory system, and death. Eating lots of protein takes lots of calcium. Some of this may be pulled from bone. Following a high-protein diet for a few weeks probably won't have much effect on bone strength. Doing it for a long time, though, could weaken bone. Long-term high-protein diets should be used with caution, if at all. Protein is present in many foods such as eggs, meat, poultry and fish in abundant amounts and these foods should be incorporated into any healthy diet. Soybeans, tofu, grains, legumes, and dairy products such as milk and cheese and other soy-based foods are an excellent alternative to red meat. Proteins can be converted into carbohydrates through a process called gluconeogenesis. It is possible that eating more protein, especially vegetable protein, may benefit the heart.

Protein and weight control: You could lose weight by cutting out carbohydrates and eating plenty of protein. High-protein, low-carbohydrate diets may work more quickly than low-fat diets.

According Harvard School of Public Health Nutrition Source, Dietary Sources of Protein are :

FOOD	Serving	Weight in Gram	Protein grams	% Daily Value*
Hamburger, extra lean	6 ounces	170	48.6	97
Chicken, roasted	6 ounces	170	42.5	85
Fish	6 ounces	170	41.2	82
Tuna, water packed	6 ounces	170	40.1	80
Beefsteak, broiled	6 ounces	170	38.6	77
Cottage cheese	1 cup	225	28.1	56
Cheese pizza	2 slices	128	15.4	31
Yogurt, low fat	8 ounces	227	11.9	24
Tofu	1/2 cup	126	10.1	20
Lentils, cooked	1/2 cup	99	9	18
Skim milk	1 cup	245	8.4	17
Split peas, cooked	1/2 cup	98	8.1	16
Whole milk	1 cup	244	8	16
Lentil soup	1 cup	242	7.8	16
Kidney beans, cooked	1/2 cup	87	7.6	15
Cheddar cheese	1 ounce	28	7.1	14
Macaroni, cooked	1 cup	140	6.8	14
Soymilk	1 cup	245	6.7	13
Egg	1 large	50	6.3	13
Whole wheat bread	2 slices	56	5.4	11
White bread	2 slices	60	4.9	10
Rice, cooked	1 cup	158	4.3	9
Broccoli, cooked	5 inch piece	140	4.2	8
Baked potato	2x5 inches	156	3	6
Corn, cooked	1 ear	77	2.6	5